bzoj 1257

商最多有sqrt（n）个。

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #define int long long
 using namespace std;
 int n,k;
 signed main()
 {
     scanf("%lld%lld",&n,&k);
     int ans=n*k;if(n>k)n=k;
     int l,r,j;
     for(int i=;i<=n;i=r+)
     {
         int y=k/i;r=k/y;
         if(r>n)r=n;
         ans-=y*(r-i+)*(i+r)/;
     }
     printf("%lld\n",ans);
     return ;
 }